1  // Copyright (c) 2017-present The Bitcoin Core developers
  2  // Distributed under the MIT software license, see the accompanying
  3  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  4  
  5  #include <util/fs.h>
  6  #include <util/syserror.h>
  7  
  8  #ifndef WIN32
  9  #include <cstring>
 10  #include <fcntl.h>
 11  #include <sys/file.h>
 12  #include <sys/utsname.h>
 13  #include <unistd.h>
 14  #else
 15  #include <codecvt>
 16  #include <limits>
 17  #include <windows.h>
 18  #endif
 19  
 20  #include <cassert>
 21  #include <cerrno>
 22  #include <string>
 23  
 24  namespace fsbridge {
 25  
 26  FILE *fopen(const fs::path& p, const char *mode)
 27  {
 28  #ifndef WIN32
 29      return ::fopen(p.c_str(), mode);
 30  #else
 31      std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>,wchar_t> utf8_cvt;
 32      return ::_wfopen(p.wstring().c_str(), utf8_cvt.from_bytes(mode).c_str());
 33  #endif
 34  }
 35  
 36  fs::path AbsPathJoin(const fs::path& base, const fs::path& path)
 37  {
 38      assert(base.is_absolute());
 39      return path.empty() ? base : fs::path(base / path);
 40  }
 41  
 42  #ifndef WIN32
 43  
 44  static std::string GetErrorReason()
 45  {
 46      return SysErrorString(errno);
 47  }
 48  
 49  FileLock::FileLock(const fs::path& file)
 50  {
 51      fd = open(file.c_str(), O_RDWR);
 52      if (fd == -1) {
 53          reason = GetErrorReason();
 54      }
 55  }
 56  
 57  FileLock::~FileLock()
 58  {
 59      if (fd != -1) {
 60          close(fd);
 61      }
 62  }
 63  
 64  bool FileLock::TryLock()
 65  {
 66      if (fd == -1) {
 67          return false;
 68      }
 69  
 70      struct flock lock;
 71      lock.l_type = F_WRLCK;
 72      lock.l_whence = SEEK_SET;
 73      lock.l_start = 0;
 74      lock.l_len = 0;
 75      if (fcntl(fd, F_SETLK, &lock) == -1) {
 76          reason = GetErrorReason();
 77          return false;
 78      }
 79  
 80      return true;
 81  }
 82  #else
 83  
 84  static std::string GetErrorReason() {
 85      return Win32ErrorString(GetLastError());
 86  }
 87  
 88  FileLock::FileLock(const fs::path& file)
 89  {
 90      hFile = CreateFileW(file.wstring().c_str(),  GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
 91          nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
 92      if (hFile == INVALID_HANDLE_VALUE) {
 93          reason = GetErrorReason();
 94      }
 95  }
 96  
 97  FileLock::~FileLock()
 98  {
 99      if (hFile != INVALID_HANDLE_VALUE) {
100          CloseHandle(hFile);
101      }
102  }
103  
104  bool FileLock::TryLock()
105  {
106      if (hFile == INVALID_HANDLE_VALUE) {
107          return false;
108      }
109      _OVERLAPPED overlapped = {};
110      if (!LockFileEx(hFile, LOCKFILE_EXCLUSIVE_LOCK | LOCKFILE_FAIL_IMMEDIATELY, 0, std::numeric_limits<DWORD>::max(), std::numeric_limits<DWORD>::max(), &overlapped)) {
111          reason = GetErrorReason();
112          return false;
113      }
114      return true;
115  }
116  #endif
117  
118  std::string get_filesystem_error_message(const fs::filesystem_error& e)
119  {
120  #ifndef WIN32
121      return e.what();
122  #else
123      // Convert from Multi Byte to utf-16
124      std::string mb_string(e.what());
125      int size = MultiByteToWideChar(CP_ACP, 0, mb_string.data(), mb_string.size(), nullptr, 0);
126  
127      std::wstring utf16_string(size, L'\0');
128      MultiByteToWideChar(CP_ACP, 0, mb_string.data(), mb_string.size(), &*utf16_string.begin(), size);
129      // Convert from utf-16 to utf-8
130      return std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>, wchar_t>().to_bytes(utf16_string);
131  #endif
132  }
133  
134  } // namespace fsbridge